Water-tube boiler



Filed July 2 5 sheets-sheet Smurf/M50@ 6 CKfw/mm l 1,618,141 Feb- 15 1927' y ac. vENNu-Mv WATER TUBE BOILER Filed July 2, 1921 5 sheets-sheet s 5WD MMO@ Q GMW/mm 1,618,141 Feb. 15 1927 G' C VENNUM WATER TUBE EOVILER Filed July 2, 1921 5 Sheets-Sheet 5 mensa ,'Feb. '15, 1927'.

GEORGE cam. vnNNUir, or wnsrrrnnnfnnwannsn.

, WATER-TUBE Borana Application led July 2,

My invention lrelates to the construction l of boilers f the water tube type and has for its object to provide a boiler which will have a maximum efficiency and capacit for a given amount of surface and, at t e Same time, great simplicity ofconstruction. My

improved boiler is characterized .in that it consists, generally speaking, fof three sections. One consists of a-l1eater section, the delivery end of which is inidirect'connection with the -steaming section-'to be' described, and which heatersection consists of a series of rows of water tubes lconnected in series in suclf a manner that the'water fed into the heater section by a pump, passes regrestion in the sense that there is no re-circulation of Water in any part'of the heater section but a steady and rapid flow from inlet end to steaming section. In order to insure a sutiiciently high rate of speed in the water flowing through the heater section I find it desirable not onlyto connect the tube rows in series with each other but also toconnect the tubes of each row. inseries. 'The heater fil'.

section of my boiler is further characterized in that it is contained in a container tiue of contracting area receiving the gases whichv have passed the steaming section at its larger end and transmitting'them among the successive tube rows at a rate of flow which is maintained at high speed notwithstanding 'the coolingmcf gases and contracting of volume. By preference, the tube rows of the` water heating section are of progressively decreasing length so as to fit into the contracting container but the tubes are of uniform length and uniform diameter and spacing, the contraction in the container beingin the side wallsA only. The opening at the end of the heater section is of the unobstructed y full length and width of the-smaller end ofr the container flue.

tubes and to provide for this contingency I',

arrange. steam traps connected with the front rows of heater tubes, which traps .are maintained in vfree communication with the steam spaces of the steaming section.

' The second main section of my boiler con 1921. serial No. 482,086.'

sists essentially of atube bank directly ex.- posed to the radiant heat of the furnace and forming the main part of a closed circuit steam enerator and through which tube bank t e gases ae drawn in a single contracting pass from front lto rear of the tube i bank so that, as the gases cool and contract their speed of transmission through the tube bank is maintained at a high rate. This part of my boiler I design to operate upon water entering it at substantially boiling temperature so that the heat transmitted through the boiler tubes to the water by radiation and convection has simply the'duty of converting the previously heated water into steam, and tojinsure that circulation in this steam- -ing section of the boiler shall be uni-directional I provide means for protecting the return tubes of the boilerv from the direct impingement of the heated gases from the furnace.

The third section of my boiler consists of i a superheater located between the steamer and heater 'sections in the direct path of the construction is to maintain the temperature differences between the gases and the water in the tube rows the highest. possible at all points along the'line of travel and also to maintain a maximum rate of heat transfer by maintaining a high` speed of gas -travel through the heatersection lto compensate for the decreasing temperature and volume of the gases` Itis also my objectto insure that the gases should pass throughthe' heater section with an even uneddying flow and for this purpose I provide for a one pass fiow of 'gases amongthe .water tubes and avoid baffling. Also I provide at the end of thecontainer flue an exit opening of the full unobstructed length and width of thisl end of the flue. Again, I maiitainthe water pass-v ing through the heating section at a high speed by reason of the series connect-ion of the tube rows and, preferably', of the tubes in the rows, and avoid all tre-circulation in the heater'setion, both because the rapid fiowlof water. through tubes facilitates heat-transfer'andbecause a rapid flow of water through the tube'sggtendsgto. prevent the formation of gas or airlbubbles adhering to the insideof the tubes with the well known 'deleteriousefect of'such formations. Otherfeatures of my invention will be best understood as described in connection with. the drawings'which illustrate a boiler construction in accordancewith my invention' and in which description of thefigures:

`Figure l' is a longitudinal view of the boiler, with one wall partially removed and certain parts-shown in section; .1

Fig. 2 is a'plan view of the boiler, with the roof partly broken away and' parts being shown in section; 0

Fig'. 3 is a rear view of the boiler, wlth the flue boxl removed; K

Fig. 4 is a section on the; line 4-4, Fig. 1,' showing the lower drum and the steam drum and. connections between the two and also the superheater;

' Fig. 5 shows a modifiedl form in which the heater section is located below the steam generating section; and y Fig. 6,1s another modified form in which the heater section is located above the steam generating section.

Referring more particularly to the drawings, theboiler isdivided into a heater section A and a vaporizing section B, the same being separate and distinct except for the connections l and v2 through the first of which water is discharged from the heater section to the vaporization section when,

and only when, it has substantially reached a vaporizingtemperature, and through the second of which is discharged any steam that maybe formed in the heater section.A

The heater section in the embodiment shown in composed of twenty-four rows of parallel'tubes -3 and 4,- the tubes li'n rowl 3 being staggered relatively to the tubes 4 (Fig. 2). 'The ends of the tubes are heid in Y headers 5, 6 there being a header for each of the respective ends of each row of heater tubes.A As shown in the drawings, the heater tubes. are divided into four sections and4 water is supplied through the-supply` pipe 7 which is connected by a valve 8 to the up per header of the rearmost row of tubes. This upper header, as shown in Fig. 3, is so constructed that water Vfloudng into said row, which header' is divided so that the` water iiows through the tubes of the Second row in series to the next lower header, and so on. There is in-each section of the heater an even number of tubes, so that the water maintained l substantially constant at al1 enters the top of the first tube and dis charges;` from the upper end.. of thelast tube in eaciifsection. The movement off the water? is alwaysfrom lthe rear of. the heater section toward the front endlthereof, and on account of't-he series arrangement, ofrela tively high velocity. |lfhe heater tubes are grouped, in four sections' 'and veach of'the three rear divisons of the heater section is connected to the supply 4pipe through an inlet valve 8 and an outletwalve 9.v Between each two valves 8` and9` there isanother valve 10 so that thev course of the Water can be directed around any particular division l if/desired, enabling anyof vthethree rear sections to be eut out fory inspection or .re- .y pair. In normal operation the valves 10 in the supply ppe'7 are closed and the valves 8 and 9 connecting the supply pipe to the several divisions of the heater are all'open.

In ease it is desired to cut out any partlcuh lar division of the heater,'the valves 8 and 9 connecting' thatsecteI-i to the supply pipe are closed'and the valve .l0 in the supply pipe between the two valves'ofthe sectionv is opened so that water flows directly past that division instead of iowing through the headers andtubes thereof. The walls of the casing of the heater Aare formed in sections.,A 11, so as to be separately removable so access can be had to -any section which. cutv out, thus enabling inspection and Apair without entirely disconnecting the yl2. l'n line with the divisionsbetween the heater sections are separating plates '13 extending froni the vsides of the divisions to the outer casing, which prevent thel hot gases from passing through the passages between the'enclosing walls and theexteriorffhter tubes. 6" are arranged troughs i4y for receiving 1 10 dust or soot which may collect in the heater section, and in these troughs are screw -conveyors .l5 which discharge suchA soot or ashes into chutes 16 leading to the ash pit i of the furnace proper. Y f .U5 The walls of the casingv surrounding the i heater. are inclined ltoward one another so that the space between the walls grows nar# rower as the rear end of thefurnace is vappreached. This results in maintaining the velocity of the flow of gas through all parts of the heater section, which velocity, if the y passage were of uniform diameter, would decrease as the rear end ofY the lfurnace is approachedv since the gases as they approach the rearA end become cooler and thereby contract so as to occupy less space. By taper-l ing the walls properly the. rate of flow of l the gas through the heater section can be Adjacent to the bottom headers-52'.v`

water connections which (permit the lowof water as above describe and also having above thelevel' of the water inisaid upper headers connections l9which permit any steam which may-be generated 'in said three front rows to pass directly to the front This front'header is connected by v header. one ormore pipes 1 to the lower part of the main 'steam drum 20 of the ,vapori'zing section and by "pipes 2vto the upper part thereof so that water flows fromsaid upperheaders into the-vapori-zing section and any steam generated inthe three front rows of the front division of the heater will pass directly' to and mingle with the steam4 inthe main steam drum.

The main steam drum 2OA forms a pait of the steam generating or -vaporizing section, which consists o fari inclinedA bank of tubes 21 of relatively smallY size located above'the fuel` bed inthe re'box 22. `The upper and lower ends of these tubes are connected to drums or headers 23 and 24 respectively, one of said drums, 23,A being vertical beneath the .main steam drum 2O and the` other` 211,

being in the same horizontal plane tl1erewith. These drums are connected to the main steam drum by large connecting pipes 25 and 26 respectively. The surface ot' the pipes 25 exposed to the gases is thereforecomparatively small relatively to the amount of water contained therein, thus reducing the tendency toward the. formation of steam in those connections. Furthermore, the vertical connections 26 between the main steam drumand thev lower drum are separated from the furnaceby the fire walls at 27 so that hot gases do not come in contact therewith at all, thus insuring against the generation of steam in thosevertical connections. The result ofthis construction is that the flow of water lthrough the Vaporizing section is uni-directional, being down through the vertical connections 26 and upward through the inclined tubes 21, which latter are directly exposedv to the radiant heat of the tire box and to the hottest' gases. The steam in the vaporizing section is, therefore, produced in the inclined pipes 21 and flowsy upward 'therethrough to the header '24 connected to the upper ends thereof, from -whence it flows through the lsiil')`sta ntially constant.

large pipes 25 to the main steam drum 2Q. The'connections 25 being. large are only partially filled 5 with water and thus perriiit the freecirculation of both water and steam and the free release of "steam lfrom the water. l Y i l-In order to increase the tube surface exposed to the direct effect of radiant lheat the inclinedtubes inthe front row of the bank 21 of the vaporizing sectionl are spaced apart twice the distance ot' the tubesl inthe remaining rows. This exposes tubes in jthe second row to the radiant heat and thereby` increases the surface so exposed and the 'amount of radiant heat absorbed.

In order to have this radiant heat act 4most efciently itv is..necessary to keep the tubes exposed to the effects of it free from dust, slag and soot, and in order to enable that to be easilyl done I pass through the upper and lower drums a series of tubes 28 whose axes are in line with the spaces beltween the tubes of the-front row of' the bank 21. This. enables me to insert a steam nozzle from time to time through the openings and fdischarge steam in the spaces between the tubes of the front row so as to keep those tubes relatively clearl from slag, soot, etc.

The inclined tubes 21 are so arranged as to comprise a bank, the width of which decreases from front to rear, each rowof tubes from front to rear being shorter than the row in front; The ends of this bank are `embracedA by two inclined walls 29 which merge with the vertical walls 27, which vertical walls form a `4passage directing the hot vgases to the heater section, which passage contains the superheater elements 30. On account of the inclined walls 29 above referred to a wide space is prcvided for the tubes exposed to radiant heat and the passage containing the other vaporizing tubes Vis rapidly contracted so that the rate of flow of hot gases as they pass between the vaporiz'ing tubes and impinge thereon is kept this passage is quite rapid because the vaporization absorbs heat rapidly, resulting. lin a rapid reduction in the'volume of the gas. The construction is preferably such as The contraction of to so increase the velocity of flow thatI the convection heating effect may be maintained fairly constant'upon 'all the inclined tubes ot the vaporizing section.

In providfng a superhealer I introduce into the upper drum adjacent each end two pipes 31 whose upper ends extend above 'the 'watei"line,v and to whosxa lower vends tivo headers 32 aie connected. Ei'om each offtliese headers U-shaped pipes 30 extend whose other ends are connected to other -headers 32 which are in turn provided with discharge ports 33 through which the steam is conducted .from the boiler. l In this way steam which is collected in the main steam l'drum before it leaves the boiler is lpassed becoming gradually warmer without any recirculation. It is then fed through the pipes 1` into the vaporizing section, and flows downward through the pipes 26 to the lower ,drum 23, whence it flows upward through "i the inclinedpipes 2l to the upper front drum 24, being at that time partially converted into steam, which steam is collected in the upper front drum'24 and led to the main steam drum where it mingles with any steam which may have reached that drum from the vforward division of the heater section.

ln this way thereis no recirculation of water between the steamer section and the heating section. There is no interference between those two sections, the heating section actin to progressively heat the water so as to discharge it to the vaporizing section in a condition to be vconverted into steam. On account of' the steam -connection between the heater section and the main steam drum, the heater section can be safely run at such a heat as to generate steam in its forward division, a thing which is-to be guarded against in connection with s o-called economizers in use at the present time.

Fig 5 shows another arrangement of the heater and vaporizing sections. The vaporizing section in this case is upright as in Fig.

l. The passage containing Ithe heaterA section, however, is a vertical passage, the gases bein led downward through it after passing t e vaporizing section. In' this case the division of the heaterwhich is nearest to the vaporizing section is connected by a pipe34 with a supplemental drum 35. The drum 35 is connected to the main steam'drum of thev vaporizingsection by a pipe 36 belowf the water level in` both drums and ybyl a pipe 37 above t'he water level in both drums. Cool water is fed intothe inlet at the lower end of the heater section. The operation is substantially the-same as the operation of the apparatus shown in Figs. 1 to 4.

p Fig'. 6 shows still another arrangement'in which the vaporizing section is turned 1 through an angle of '90 degrees and the heater section is located above the same, the

gases passing directly ,upward through thevaporzing section to the heater section and plemental v drum 40.

thence to the'flue. In this case the lowermost division of the heater is the section in which 3 the water is the hottest and this section is formed witha steam trap 38 which is connected by'a. `tube 39 to a supplemental drum 40. The highly heated water and arfy steam which may be formed in the heater section goes upward through'thepipe 39 to the sup- Leading `from this drum is' a pipe 41 which extends upward half way above the bottomof that drum and connects with the lower end of the main steam drum 42 so that while the drum 40 is kept half filled with water, water flows from the drum 40 to the drum 42. A pipe 43 which extends intothe upper half of the drum 40 is connected with the upper portionV y of the drum 42 and serves to conduct steam which may be discharged by the lower heater `section into the-drum 40 directly to the steam space in thedrum 42.

From the foregoing it will be seen that my invention may be adapted to varying condi- 'tions which may exist in different plants,

it being .possible to locate the elements in a horizontal series, or to locate the heater below the vaporiz'ing section or-above the-same y `or at an angle thereto. In' every case the ai'- rangement providesfor a single pass of the hot gases and does not require baflie .plates or other devices which are liable to form gas of operation. i Y

As will be evident to those skilled in the art, my invention permits of various modil ications without departing from the spirit thereof or the scope of the appended claims.

What l claim is:

pockets which interferewith the efficiency 1. A' boiler comprising a closed circuit steaming section of the water tube type having a tube bank made up of multiple rows of tubes and directly exposed to the heat of the fire box, invv combination with means for directing thefire gases through the tube bank of the steaming section in a single pass p and through .a contracting area, so as to maintain said gases at high speed of trans-` mission, a water heating section connected to directly supply the steaming section and 115 made up of multiple rows of i' watertubes connected together in series so as to mainfrom rear to front and directly into the steaming section, said water heating section being of such heatingcapacity as will heat the water to approximately thesteaming temperature before delivering it vto the steaming section and a flue container for said heating section connected to receive the gases directly from the steaming'section and contracting from front to rear so as to maintain the gases at a high speed of transmission. v

.2. A boiler comprisingv `a closed circuit steaming section of the water tube type hav- 'tain a one direction flow of water therein p ing. a tube bank made up of Amultiple rows of tubes and directly .exposed to the heat ofthel ire box, said steaming section having return tubes .for the downward ow of water located outsidev of the pathof the ire gases, in combination with means for directing the re gases through the 'tube bank of` a line container for said heating section connected to receive the gases directly from the steaming section and contractingfrom front to rear so as to maintainthe gases at a high speed of transmission 3. A Vboiler j'comprising a closed circuit Y- steaming section of the watertube type having. a tube bank Vmade up of multiple rows of tubes and directl exposed to the heat of the lire box, in com ination with means for ,directing the ire gases through the tube bank ofthesteaming'section in a single pass and through a contracting area, so as to maintain said. gases at high speed of translmission, a water heating section connected to directly supply the steaming section and made up of multiple rows of water tubes in which the tubes of each row are connected in series and each successive row is also convnected in series so as to maintain a one direction rapid flow of Awater through sai'd L heating section and intojthe steaming section, said water heating section being of Isuch heating capacity as will'heat the water to :approximately the steaming temperature befoije delivering it to the steaming section Vand a flue container for said heating section "connected to receive 'the gases directly from the steaming section and contracting from front to rear so as to maintain the gases. at a high speed of transmission.

4. A boiler comprising a closed circuit steaming section of the water tube type having a tube bank made up of multiple rows of tubes and directly 'exposed to the heatof the tire box, in combination with means for 'directing the fire gases through lthe tube bank of the steaming section in a single pass and through a' contracting area,

so as to maintain said gases at high speed of transmission, a water heating section cony fnected to directly supply the steaming section Vand made up of multiple rows of Water tubes of equal height and progressively decreasing length from front to rear, said rows of tubes being connected togetherin series so as to maintain a one direction new of water therein from rear to front and directly into the steaming section, said water heating section being of' such heating capac- 'ity as will heat the Water to approximately the steaming temperature before "delivering it to the steaming section and a ue container for said heating section connectedto receive the gases directly from the steaming section and 'contracting froml front to rear so as to maintain the gases at a high speed of transmissiomV 5. A boiler comprising a closed circuit steaming section of the water tube type having a tube bank made up of multiple rows of tubes and directly exposed tothe heat of the tire box, in combination with means l for directing the fire gases-through the tube .bank of the steaming section in a single passand through a contractingA area, so as -to maintain said gases at high speed of trans- -missiomal water heating section connected, to directly supply the steaming section and' made up of multiple rows of 'water tubes connected together in series so as to. maintain a one direction low of Water therein from rear to front and directly into the steaming section, said water heating section being of such heating capacity as will heat the water to approximately th'-, steaming temperature before deliver-ing itv to the steaming section, a flue container for said heating section connected to receive .the gases directly from the steaming section and contracting from front to rear so as to maintain the gases 'at a high speed of transmission and a superheater located in the gas pass between the steaming and heating sectin of the boiler.

6. A boiler comprising a closed circuit steaming section of the'water tube type hav- .ing a tube bank made up of multiple rows of tubes and 'directly exposed to the heat of the fire box, said rows of' tubes connecting at top and bottom with common headers, said steaming section having also a steam and water drinn connected to the common headers of the tube bank, in combination with means for directing the fire gases through lthe tube bank of the steaming ysection in a single pass and through a contractinglarea, so as to maintain said gases at high speed of transmission, a water heating section connected to directly supply the steaming section and made up of multiple rows of Water maintainr a one direction flow of water therein from rear. to front and directly into .thesteaming section, said Water heating section being ot such heating capacity as will heat the water to approximately the 'steamies `tubes connected together in series so as to ing -temperature betere delivering'it to the f steaming section and a flue container for `said heating section connected to receive the gases directly from the steaming section and y tain the contracting from front to rear so as to maini gases at a high speed of .transmission.A vf 7 A boiler comprising a closed circuit steaming section of the water tube type having a tube bank made up of multiple rows of tubes and 'directly exposed to the heat of of transmission, a water heating section connected to directly supply the steaming section and made up of multiple rows of water tubes i`n which the tubes of each row are connected in series and each successive row is also connected in series so as to maintain a 'one -direction rapid flow of water through said heating section and into the'steaming t section, said water heating section being of such heating'capacity as will heat the water to approximately .the steaming temperature before delivering 1t to the' steammg section and a flue container for said heating section.

' connected to receive the gases directly from the steaming section and 'contracting from front to rear so as to maintain the gases 4atsa a high speedof transmission;

steaming sectionof the water tube type having a tube bank made up of multiple rows of tubes and directly exposed tothe heat of thelire box, said rows of tubes connecting 8. A boiler comprising a closed circuit at (op and bottom with common headers, j said steaming section having also a steam and .Water .drum connected to the common headers of the. tube bank, in combination with means. for directing the lire gases through lhetube bank of the steaming section in a single pass and through a contracting area, so, as to maintain said gases at high speed of transmission, a water heating section connected to directly supply the steaming section and made up of multiple rows of water tubes of equal height and progressively decreasing length'from front to rear, said rows of tubes beingconnected together in series so as to maintain a one direction iiow of water therein from rear to front and directly into the steaming section, said water heating section being of such heating capacity as will heat the water to approximately the seaming temperature before delivering it to the steaming section and a flue container for said heating section connected to receive the gases directly from the steaming section and contracting from front to rear so as to maintain the gases -a`t a high speed of transmission.'

' GEORGE CARL'VENNUM. 

